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TIME-KEEPING   IN    LONDON. 


REPRINTED    FOR   DISTRIBUTIOlv    BY    THE 
OBSERVATORY    OP   WASHlNGTOaN    UNIVERSITY,   ST.   LOUIS. 


From  The  Poptdar  S£ienc£  Monthly^  December,  1882,  January,  1883. 


BY 

EDMUND    A.    ENGLER. 


NEW  YORK: 
D,  APPLETON  AND  COMPANY. 

1883. 


■-■ge  lecQfpi 


TIME-KEEPING   IN   LONDON. 


REPRINTED    FOR    DISTRIBUTION    BY    THE 
OBSERVATORY    OF    WASHINGTON    UNIVERSITY,    ST.    LOUIS. 


From  The  Popular  Science  Monthly,  December,  1882,  January,  i88j. 


BY 


EDMUND    A.    ENGLER 


NEW  YORK: 

D.   APPLETON  AND  COMPANY. 

1883. 


TIME-KEEPING    IN    LONDON 


IT  is  proposed  in  this  paper  to  describe  sonie  special  features  of  the 
instruments  by  which  time  is  kept  at  the  Royal  Observatory, 
Oreenwich,  the  means  for  correcting  them,  and  the  methods  and  in- 
struments by  which  time-signals  are  distributed  from  the  observatory 
to  London  and  elsewhere. 

The  primary  standard  time-keeper  of  England  is  a  sidereal  clock 
kept  in  the  basement  of  the  Royal  Observatory,  Greenwich.  This 
clock  is  of  the  best  construction,  and  is,  moreover,  provided  with  the 
most  approved  apparatus  for  compensation  and  correction. 

Experience  has  shown  that  the  best  results  are  obtained  when  the 
connection  between  the  driving- weight  and  the  pendulum  of  a  clock 
is  as  slight  as  possible.  This  has  been  accomplished  in  the  Greenwich 
clock  by  the  use  of  an  elegant  escapement,  the  details  of  which  are 
shown  in  Fig.  1,*  representing  a  back  view  of  the  clock-train.  The 
crutch-axis,  supported  by  the  arm  (e)  and  the  back  plate  (b)  of  the 
clock-train,  carries  an  arm  (e),  attached  at  f  to  the  left-hand  pallet 
arm.  The  pallets  are  carried  by  the  crutch-rod  (d).  At  ^is  attached 
a  detent  projecting  toward  the  left  and  ending  in  a  light  curved 
spring.  Near  the  top  of  the  escape-wheel  this  detent  carries  a  jew- 
eled pin  which  locks  the  wheel.  The  action  is  as  follows  :  When  the 
pendulum  swings  toward  the  left,  the  arm  (e)  lifts  the  delicate  spring 
at  the  end  of  the  detent,  the  wheel  is  released  and  drops  forward  so 
that  a  tooth  presses  against  the  face  of  the  pallet  and  gives  an  im- 
pulse to  the  pendulum  ;  the  spring  at  the  end  of  the  detent  immedi- 
ately locks  the  wheel  again,  and  the  pendulum  swings  on  freely  to  the 
left.    When  the  pendulum  swings  to  the  right,  the  light  spring  at  the 

*  Figs.  1,  3,  4,  5,  and  6,  have  been  taken  from  Lockyer's  "Stargazing,"  through  the 
courtesy  of  Macmillan  &  Co.,  London,  publishers,  by  permission  of  the  author. 


TIME-KEEPING   IN   LONDON. 


end  of   the  detent   lets  it  pass  without  unlocking  the  wheel.      The 
right-hand  pallet  is  only  intended   to    catch    the   wheel   in  case    of 


\ 


accident  and  forms  no  essential  part  of  the  escapement.  Thus,  it 
will  be  seen,  the  pendulum  is  quite  free  except  during  a  part  of  every 
alternate  second,  when  it  releases  the  escapement  and  receives  an 
impulse  ;  the  seconds-hand,  attached  to  the  escape-wheel,  moves  only 
once  every  two  seconds. 


TIME-KEEPING   IN   LONDON. 


I 


The  most  important  source  of  error  in  the  running  of  a  fine 
•clock  is  the  change  in  the  length  of  the  pendulum  due  to  change 
of  temperature.  Two  methods 
suggest  themselves  of  eliminat- 
ing this  error  :  1.  To  put  the 
clock  where  it  will  not  be  sub- 
ject to  changes  of  temperature. 
2.  To  counteract  the  effect  of 
changes  of  temperature.  To  this 
end  various  kinds  of  pendulums 
have  been  devised,  notably  the 
mercurial  and  gridiron  forms, 
which  are  known  under  the  gen- 
eral name  of  "compensating  pen- 
dulums." At  Greenwich  the  two 
methods  are  combined  to  insure 
complete  success.  The  clock  is 
placed  in  the  magnetic  basement 
of  the  observatory,  where  the 
temperature  is  as  nearly  uniform 
as  possible,  and  apparatus  is  pro- 
vided to  annul  the  effect  of  any 
change  of  temperature  which 
might  occur. 

Tests  made  with  a  mercurial 
pendulum  disclosed  the  fact  that 
the  steel  rod  responded  more 
■quickly  than  the  mercury  to  a 
change  of  temperature,  and  that 
consequently  an  appreciable  in- 
terval of  time  was  required  for 
perfect  compensation ;  a  modi- 
:fication  of  the  gridiron  form, 
«hown  in  Fig.  2,  was  therefore 
adopted.  The  pendulum  w^as  de- 
signed by  Messrs.  E.  Dent  &  Co., 
of  London,  for  the  Transit  of 
Yenus  Expedition  (1874),  but  has 
since  been  used  for  the  primary 
standard  time-keeper  of  the  Uni- 
ted Kingdom.  Its  construction 
will  be  best  understood  by  refer- 


iijl  i 


6 


TIME-KEEPING   IN    LONDON. 


ence  to  the  section  shown  in  Fig.  3.  To  the  lower  end  of  a  steel  rod^ 
suspended  in  the  ordinary  manner,  is  attached  the  screw  for  rating  the 
pendulum.  On  this  screw  and  surrounding  the  rod  rests  a  zinc  tube, 
extending  upward  ;  inclosing  the  zinc  tube  and  attached  to  its  top  is  a 
steel  tube  extending  downward  ;  on  a  collar,  at  the  lower  end  of  the 
steel  tube,  hangs  the  cylindrical  leaden  bob,  attached  at  its  center. 
Slots  and  holes  are  cut  in  the  tubes  in  order  to  equally  expose  all  parts. 
The  following  table,  taken  from  the  official  records  of  the  Royal 
Observatory,  is  published  by  Messrs.  E.  Dent  &  Co.,  for  the  purpose 
of  showing  the  performance  of  a  clock  with  steel  and  zinc  pendulum  : 

CLOCK— DENT   1914. 


DATE. 


Days.  Hours 

IS^l— September    3  21.. 

17  21.. 

24  21.. 

October         1  22. . 

8  21.. 

15  21.. 

22  21.. 

29  21.. 

November     5  22. . 

12  22.. 

19  21.. 

26  22.. 

December     3  21., 

10  22.. 

17  21.. 
26  0.. 
31  22.. 

1872— January        7  22. . 

14  21.. 

21  21.. 

28  22.. 

February      4  22. . 

11  22.. 

18  21.. 
26  22.. 

March           3  21. . 

10  22. . 

17  21.. 


Mean  daily 

Average  tem- 

Clock slow  of  Green- 

losing rate 

perature  of 

wich  sidereal  time. 

during  each 

external 

interval. 

air. 

Minutes. 

Seconds. 

Seconds. 

14 

31-8 

15 

34-1 

4-4 

62° 

16 

2-3 

4-0 

54 

16 

34-2 

4-5 

50 

17 

51 

4-4 

52 

17 

36-9 

4-5 

46 

18 

8-2 

4-5 

54 

18 

37-8 

4-2 

47 

19 

7-8 

4-3 

47 

19 

36-2 

4-1 

39 

20 

5-8 

4-3 

35 

20 

36-3 

4-3 

34 

21 

6-7 

4-4 

36 

21 

33-9 

3-9 

30 

22 

6-6 

4-7 

40 

22 

45-2 

4-8 

42 

23 

13-2 

4-7 

43 

23 

46-3 

48 

42 

24 

20-7 

4-9 

40 

24 

54-2 

4-8 

39 

25 

30-2 

5.1 

42 

26 

6-4 

5-2 

44 

26 

41-4 

6-0 

47 

27 

16-0 

5-0 

44 

27 

50-0 

4-8 

45 

28 

241 

4-9 

46 

28 

58-1 

45 

49 

29 

31-2 

4-8 

45 

During  the  whole  time  of  rating,  the  clock  was  situated  in  a  small 
hut  erected  for  observing  the  Transit  of  Venus.  No  record  of  the 
temperature  of  the  hut  was  kept,  but  the  variations  would  be  very 
similar  to  those  of  the  external  air,  whose  average  temperature  for 
each  interval  is  given  in  the  table. 


TIME-KEEPING   IN   LONDON.  7 

The  compensating  action  of  the  pendulum  evidently  depends  upon 
the  relative  lengths  of  steel  and  zinc,  and  it  is  easily  possible  that 
great  difficulty  would  be  experienced  in  cutting  and  fitting  tubes  of 
exactly  the  right  length  ;  to  complete  the  adjustment  a  very  delicate 
contrivance  is  added. 

Two  compound  bars  of  brass  and.  steel  {h  and  ^,  Fig.  1),  with  small 
weights  at  their  ends,  are  hung  to  the  crutch-axis  by  means  of  a  collar 
loose  enough  to  be  easily  turned.  The  rods  are  so  made  that  under 
normal  conditions  the  brass  and  steel  are  of  the  same  length,  and  the 
two  bars  are  in  the  same  straight  line  ;  the  center  of  gravity  of  the 
rods  and  the  weights  (regarded  as  one  body)  is  therefore  in  the  axis,, 
and  the  weights  are  balanced  in  every  position,  no  matter  what  angle 
the  line  of  the  rods  makes  with  the  plane  of  the  horizon  ;  they  affect 
the  pendulum  only  by  their  inertia.  But,  when  a  change  in  tempera- 
ture occurs,  the  brass  and  steel  become  of  unequal  length,  owing  to  a, 
difference  in  the  co-efficients  of  expansion  of  the  two  metals,  the  rods 
are  bent,  and  the  center  of  gravity  of  the  rods  and.  weights  is  no  long- 
er in  the  axis,  nor  is  it  in  the  same  vertical  plane  as  the  axis  except 
when  the  weights  are  in  a  horizontal  line  ;  so  that  an  unbalanced  force 
is  introduced  whose  compensating  action  varies  from  a  maximum 
when  the  weights  are  in  a  horizontal  line,  to  zero  when  the  weights  are 
in  a  vertical  line.  To  be  explicit,  suppose  the  rods  to  be  horizontal 
and  the  brass  uppermost,  and  let  there  be  an  increase  of  temperature. 
The  brass  will  expand  more  than  the  steel,  and,  the  rods  being  bent 
downward,  the  weights  will  be  lowered.  As  the  pendulum  swings 
the  weights  swing  with  it,  and  are  continually  trying  to  get  back  to  a 
horizontal  position  where  they  would  balance  each  other  ;  if  they  were 
swinging  alone,  they  would  evidently  swing  faster  than  the  pendulum^ 
and  therefore,  being  attached,  they  accelerate  its  motion.  If  the  steel 
were  uppermost,  the  weights  would  be  raised  with  an  increase  of  tem- 
perature and  the  pendulum  retarded.  If  the  rods  were  both  vertical, 
a  change  of  temperature  would  only  throw  the  center  of  gravity  of 
the  two  weights  to  one  side  or  the  other  of  the  axis,  but  would  not 
raise  or  lower  it  ;  this  would  only  introduce  a  continuous  force  tend- 
ing to  make  the  pendulum  oscillate  farther  on  one  side  than  the  other, 
but  not  affecting  its  rate.  At  intermediate  positions  between  the  ver- 
tical and  horizontal,  the  change  in  the  position  of  the  center  of  gravity 
due  to  a  change  of  temperature  would  vary  with  the  angle  made  by 
the  line  joining  the  centers  of  gravity  of  the  two  weights  with  the 
plane  of  the  horizon  ;  any  required  compensating  action,  between  the 
limits  above  mentioned,  for  a  known  change  of  temperature,  can  there- 
fore be  obtained  by  setting  the  rods  at  the  proper  angle. 


s 


TIME-KEEPING   IN   LONDON. 


In  order  to  make  a  small  change  in  the  rate  without  stopping  the 
pendulum,  the  device  shown  in  Fig.  1  has  been  employed  :  A  weight 
{k)  slides  freely  on  the  crutch-rod  shown  back  of  it  in  the  figure,  but 
is  held  by  the  screw  on  the  end  of  the  spindle  (/)  which  hangs  from 
the  nut  (m)  at  the  crutch-axis.  By  turning  the  nut  (m)  the  weight 
(k)  can  be  lowered  or  raised,  and  this  makes  the  clock  gain  or  lose. 

But  the  nicety  of  the  correction  of  variations  due  to  changes  of 
temperature  has  brought  to  light  variations  due  to  another  cause 
commonly  quite  overlooked  ;  it  has  been  found  that  the  pendulum  is 
affected  by  changes  of  barometric  pressure.  A  change  in  the  ba- 
rometer of  an  inch  and  a  half  will  sensibly  alter  the  rate  of  the  pen- 
dulum.    The  difficulty  might  be  avoided  by  placing  the  clock  in  a 


Fig,  4.— Greenwich  Clock  :  Abrangkment  for  Compensation  tor  Barometric  Pressttrb. 


vacuum,  but  this  is  evidently  impracticable.     In  the  Greenwich  clock 
the  method  shown  in  Fig.  4  has  been  adopted  to  counteract  the  effects 


TIME-KEEPING   IN    LONDON.  9 

of  barometric  changes.  To  the  pendulum-bob  are  attached  two  verti- 
cal bar-magnets,  one  in  front  (a)  with  the  north  pole  down,  the  other 
at  the  back  (and  therefore  not  shown  in  the  figure),  with  the  south  pole 
down.  Below  these  and  normally  at  a  distance  of  3f  inches  from 
them  is  a  horseshoe  magnet  (b)  which  hangs  on  one  end  of  a  lever  (c) 
nicely  balanced  on  knife-edges  at  A  ;  the  other  end  of  the  lever  (c) 
rests  by  means  of  a  rod  (d)  on  a  float  (e)  in  the  shorter  leg  of  a  siphon 
barometer.  Counterpoises  are  added  at/* to  balance  the  magnet  (b). 
A  plan  of  the  lever  on  a  smaller  scale  and  a  section  at  A  are  also 
shown  in  the  figure.  The  barometer-tube  is  made  so  much  larger  in 
the  shorter  than  in  the  longer  leg  that  a  change  of  one  inch  in  the 
barometer  would  move  the  float  in  the  shorter  leg  only  two  tenths  of 
an  inch.  A  rise  or  fall  in  the  barometer  causes  a  corresponding  mo- 
tion in  the  horseshoe  magnet,  and  thus  varies  the  intensity  of  its 
attraction  for  the  magnets  on  the  pendulum-bob.  By  proper  adjust- 
ment this  varying  attraction  is  made  to  furnish  the  required  compen- 
sation. 

The  small  error  which  remains,  notwithstanding  the  above-detailed 
provisions  for  correction,  is  allowed  to  accumulate,  but  is  determined 
daily  (unless  clouds  prevent)  by  transit  observations,*  so  that  the  exact 
sidereal  time  is  always  known. 

The  standard  sidereal  clock  registers  its  beats  upon  the  chronograph 
record  ;  controls,  by  electric  connection,  all  the  sidereal  clocks  in  the 
different  rooms  of  the  observatory  ;  and  drives  a  sidereal  chronometer 
{b,  F\g.  5),  in  agreement  with  itself,  in  the  computing  and  time-dis- 
tributing room. 

The  secondary  regulator  of  the  time  of  England  is  the  mean  solar 
standard  clock  at  the  Royal  Observatory,  which  was  specially  erected 
in  1852  for  service  in  the  time-signal  system,  of  which  it  is  now  the 
most  important  instrument.  This  clock  has  a  seconds-pendulum, 
which  closes  an  electric  circuit  as  it  swings  to  the  right.  An  electro- 
magnet in  the  circuit  lifts  a  small  weight,  which  is  discharged  upon 
the  pendulum  as  it  swings  to  the  left,  and  gives  it  an  impulse  ;  this 
being  repeated  at  each  vibration  is  suflicient  to  keep  it  in  motion.  The 
pendulum  also  closes  other  galvanic  circuits — one  as  it  swings  to  the 
right,  another  as  it  swings  to  the  left — which  send  currents  alternately 
positive  and  negative  through  electro-magnets,  alternately  attracting 
and  repelling  bar-magnets  fastened  to  an  axis,  which  thus  receives  a 

*  The  difference  between  the  clock-time  of  the  transit  of  a  star  over  the  meridian 
(corrected  for  errors  of  position  of  the  instrument,  and  for  "  personal  equation  ")  and  the 
right  ascension  of  the  star  for  the  day,  taken  from  the  nautical  almanac,  is  the  error  of 
the  clock. 


10  TIME-KEEPING   IN   LONDON. 

reciprocating  motion.  An  arm  projecting  from  this  axis  moves  the 
seconds- wheel  one  tooth  forward  each  second  ;  proper  gearing  gives 
motion  to  the  minute  and  hour  wheels. 

The  mean  solar  standard,  besides  controlling  other  clocks,  to  be 
enumerated  later,  drives  a  seconds-relay  {a,  Fig.  5),  which  controls  a 
mean-time  chronometer  (c). 

All  the  clocks  controlled  by  the  mean  solar  standard  are  required 
to  indicate  exact  Greenwich  local  time  ;  the  error  can  not  therefore  be 
allowed  to  accumulate,  and  the  means  of  correction  are  provided. 
Carried  by  an  arm  projecting  from  the  pendulum-rod  of  the  mean 
solar  standard  is  a  magnet,  five  inches  long,  which  swings  just  over  a 
hollow  galvanic  coil,  called  "  the  accelerating  or  retarding  coil,"  fast- 
ened to  the  clock-case  and  operated  by  a  special  battery.  The  attrac- 
tion or  repulsion,  between  the  magnet  and  the  coil,  produced  b}^  send- 
ing currents  in  opposite  directions,  gives  any  required  acceleration  or 
retardation  to  the  pendulum.  Care  must,  of  course,  be  taken  that  the 
correction  be  not  made  too  quickly,  else  the  clock,  instead  of  being 
controlled  by  the  current,  will  break  away  from  control,  and  the  error 
will  be  increased.  It  is  now  so  arranged  that  the  .current  will  produce 
a  correction  of  one  second  in  about  ten  seconds.  The  correction  is 
made  as  follows  :  Between  the  sidereal  chronometer  {b,  Fig.  5)  and  the 
mean-time  chronometer  (c)  there  is  a  commutator  {d).  By  moving  its 
handle  toward  the  right,  a  current  is  sent  through  the  "  accelerating  or 
retarding  coil  "  which  accelerates  the  mean  solar  standard  ;  by  moving 
the  handle  toward  the  left,  the  current  goes  through  the  coil  in  the 
opposite  direction,  and  retards  the  mean  solar  standard  ;  in  the  inter- 
mediate position  (shown  in  the  figure)  no  action  takes  place.  The 
operator,  having  ascertained  the  error  of  the  sidereal  standard  and  its 
sympathetic  chronometer,  by  astronomical  observation  as  described, 
applies  this  error  to  the  face-reading  of  the  sidereal  chronometer,  and 
gets  the  exact  sidereal  time  ;  by  simple  reduction  he  finds  the  corre- 
sponding mean  solar  time,  and,  by  comparison,  the  error  of  the  mean- 
time chronometer ;  he  then  moves  the  handle  of  the  commutator,  and 
corrects  the  error  of  the  mean  solar  standard,  and  of  all  the  clocks 
controlled  by  it,  without  leaving  his  position  in  the  computing-room. 
This  correction  can  be  made  at  any  instant  when  the  exact  time  is 
desired  ;  it  is  usually  made  at  10  a.  m.  and  1  p.  m.,  because  at  those 
hours  a  general  distribution  of  time-signals  takes  place. 

The  mean  solar  standard  serves  for  the  distribution  of  accurate 
time  in  the  following  ways  : 

Nearly  all  the  mean-time  clocks  in  the  Royal  Observatory  are  driven 
by  the  standard  clock  ;  they  are,  in  fact,  simply  dials  whose  hands  are 


TIME-KEEPmG   IN   LONDON. 


11 


moved  in  the  same  way  and  by  the  same  battery  as  the  hands  of  the 
standard  itself.  These  clocks  are  placed  in  the  various  rooms  of  the 
observatory,  so  that  the  astronomers  have  the  exact  time  close  to  any 


12  TIME-KEEPING   IN   LONDON. 

of  their  instruments.  One  of  them  is  in  the  wall  surrounding  the 
grounds,  and  will  be  familiar  to  every  one  who  has  visited  the  observa- 
tory ;  several  are  placed  in  the  chronometer-room,  where  the  navy  and 
other  chronometers  are  corrected  and  regulated. 

The  seconds-relay  («,  Fig.  5),  already  referred  to,  is  also  driven  by 
the  mean  solar  standard. 

Until  1880  the  standard  clock  controlled,  by  seconds-beats,  a  num- 
ber of  clocks  on  a  private  wire  in  London,  which  were  made  to  beat 
synchronously  with  the  standard  by  an  application  of  the  Jones  sys- 
tem,* in  which  the  electric  current  is  used,  not  as  a  driver,  but  as  a 
regulator  of  clocks  already  running  with  small  error  and  by  means 
of  their  own  motive  powers.  This  plan,  though  still  used  within  the 
observatory,  has  been  abandoned  in  London. 

With  the  standard  clock  is  connected  another  electric  circuit,  open 
in  two  places.  These  are  both  automatically  closed  by  the  clock,  one 
at  the  end  of  each  minute,  but  the  other  only  for  some  seconds  on 
either  side  of  the  end  of  each  hour  ;  so  that  they  are  both  closed  only 
at  the  end  of  each  hour,  and  then  only  can  the  current  pass. 

This  hourly  current  acts  on  the  magnet  which  drops  the  Greenwich 
time-ball  daily  at  one  o'clock,  and  on  the  magnet  of  the  hourly  relay 
(to  the  left  in  Fig.  5)  which  completes  several  independent  circuits, 
each  controlling  a  separate  line  of  wire.  One  of  these  extends  to  the 
central  telegraph  station  at  the  General  Post-Office  in  London,  and 
another  to  the  London  Bridge  Station  of  the  Southeastern  Railway. 
The  bell  and  galvanometer  marked  in  Fig.  5  "  P.  O.  Telegraphs  "  and 
"  S.  E.  R.  Hourly  Signal  and  Deal  Ball "  show  the  passage  of  these 
currents. 

Thus  far  the  service  is  under  the  control  of  the  astronomer  royal, 
and  he  holds  himself  responsible  to  send  the  signals  described  along 
each  line  every  hour  of  the  day  and  night  with  the  greatest  attainable 
accuracy.  The  signals  are  generally  correct  within  one  tenth  of  a 
second  of  error.  Should,  however,  by  any  accident,  an  hourly  signal 
be  in  error,  even  to  half  a  second,  another  signal  is  immediately  sent, 
announcing  that  the  last  was  not  reliable.  Sj^ecial  pains  are  then 
taken  that  the  next  hourly  signal  be  correct.  Here  the  responsibility 
of  the  astronomer  royal  (except  for  the  dropping  of  the  Deal  ball,  to 
be  explained  later)  ends. 

On  the  other  hand,  it  is  to  be  remarked  that  the  Post-Office  Depart- 
ment, which  undertakes  the  distribution  of  these  signals  to  London 

*  For  an  illustration  of  the  Jones  systeno  for  regulating  clocks  at  a  distance,  see  artic.e 
on  "  Time-keeping  in  Paris,"  "Popular  Science  Monthly,"  January,  1882. 


TIME-KEEPING-   IN    LONDON. 


IS 


and  the  country,  agrees  to  furnish  subscribers,  not  with  correct  sig- 
nals, but  with  the  signals  which  they  receive  from  Greenwich.  The 
Greenwich  signals,  however,  being  considered  everywhere  in  England 


as  absolutely  correct,  constitute  a  standard  from  which  there  is  no 
appeal. 


14 


TIME-KEEPING   IN   LONDON. 


The  distribution  of  the  Greenwich  signals  from  the  General  Post- 
Office  in  London  is  effected  by  means  of  the  Chronopher  or  Time- 


carrier,*  shown  in  perspective  in  Fig.  6,  and  in  front  elevation  in  Fig. 
7.\     To  this  instrument  the  hourly  signal  from  the  observatory  is  sent 


*  There  are  actually  two  of  these ;  the  one  shown  in  the  figure  is  the  new  and  larger  one. 
I  For  a  description  of  the  chronopher,  from  which  the  above  is  condensed,  and  for 


TIME-KEEPING   IN   LONDON.  15 

by  means  of  a  special  under-ground  wire.  Branching  out  from  it  are 
four  groups  of  wires  :  1.  Metropolitan,  running  to  points  in  London 
only.  2.  Promncial  Short,  to  points  not  more  than  fifty  miles  from 
London,  as  Brighton,  etc.  3.  Provincial  Medium,  to  points  farther 
away,  as  Hull,  etc.  4.  Provincial  Long,  to  extreme  points,  as  Edin- 
burgh, Belfast,  etc.*  The  ends  of  each  of  the  four  groups  are  brought 
together,  and  each  group  has  a  separate  relay,  in  order  that  the  shorter 
may  not  unduly  deprive  the  longer  lines  of  their  share  of  the  current. 
The  four  relays  are  all  worked  by  the  hourly  signal  from  Greenwich, 
and  therefore  act  simultaneously.  The  lines  of  the  Metropolitan  group 
-are  used  only  for  time  purposes,  and  are  therefore  always  connected 
with  their  relay,  and  distribute  the  signals  hourly.  But  the  lines  of 
the  other  groups  are  in  use  generally  for  ordinary  telegraphic  pur- 
poses, and  distribute  time-signals  only  at  ten  and  one  o'clock.  At  these 
bours,  therefore,  the  wires  must  be  switched  off  from  their  ordinary 
duty,  and  placed  in  communication  with  their  respective  relays  to  be 
ready  to  receive  the  time-signals.  The  electrical  working  of  the  appa- 
ratus which  accomplishes  this  will  be  understood  by  reference  to  Fig. 
8.f  Under  normal  conditions,  the  current  from  the  observatory  passes 
directly  through  the  chronopher,  and  out  at  the  galvanometer  G',  to 
the  tower-clock  at  the  Houses  of  Parliament,  Westminster.  This  clock 
has  a  gravity  escapement,  and  a  metallic  compensating  pendulum, 
very  similar  to  the  pendulum  of  the  Sidereal  Standard,  already  de- 
scribed, and  runs  with  a  rate  of  less  than  one  second  per  week.  The 
current  from  Greenwich  in  no  way  controls  the  Westminster  clock, 
but  is  simply  used  for  rating  the  clock  by  comparison  ;  when  change 
of  rate  is  necessary,  weights  are  added  or  removed  at  the  pendulum. 

Each  of  the  line  wires  is  in  permanent  connection  with  one  of  a  set 
of  jointed  vertical  bars  (B,  B',  B"),  which,  except  at  the  times  for  the 
signal,  are  kept  in  contact  by  springs  with  cocks  in  the  circuit  of  the 
wire  ;  but  at  the  times  for  the  signal  a  long  metallic  bar  (C)  acting  as 
a  cam  (better  shown  in  Fig.  7,  in  front  of  the  vertical  bars),  is  made 
by  clock-work  to  disconnect  all  these  bars  from  their  instruments.  The 
bar  (C)  is  divided  into  three  parts,  corresponding  to  the  long,  medium, 
and  short  provincial  lines,  insulated  from  each  other,  and  connected 
respectively  with  the  bars  of  the  relays  (V,  V,  Y")  through  the  galva- 

drawings  from  which  Figs.  '7,  8,  and  9  have  been  made,  the  writer  is  indebted  to  Will- 
iam II,  Preeee,  Esq.,  Superintendent  of  Telegraphs,  London. 

*  The  Greenwich  signals  are  sent  into  Ireland  only  for  purposes  of  comparison ;  Dub- 
lin time  is  used  throughout  the  island. 

•f  The  small  figures  1,  2,  3,  4,  to  the  right  of  Fig.  8  and  to  the  left  of  Fig.  9,  show  the 
connection  between  the  wires 


16 


TIME-KEEPING   IN    LONDON. 


TIME-KEEPING   IN    LONDON.  lY 

Tiometers  (g,  g',  g\  Fig.  8).  The  left  or  rest  contacts  of  these  relays 
are  in  connection  with  the  zinc  poles  of  separate  batteries,  whose  cop- 
per poles  are  grounded,  so  that,  when  the  bars  of  these  relays  are  put 
in  connection  with  the  line  wires,  a  zinc  or  "  preliminary  "  current  is 
ready  to  be  sent  out  ;  this  current  prevents  the  distant  relays  from 
being  actuated  by  contacts  or  accidental  currents,  and  serves  as  a 
warning  signal.  The  right-hand  contacts  of  the  relays  are  connected 
respectively  with  the  copper  poles  of  separate  batteries  whose  zinc  poles 
are  grounded,  so  that,  when  the  bars  are  moved  over  to  the  right  (which 
is  done  by  the  incoming  Greenwich  current),  the  outgoing  current  is 
reversed,  and  this  constitutes  the  signal.  The  relay  Y'"  is  for  dis- 
tributing the  signals  only  to  points  in  the  metropolis,  and,  as  the  wires 
on  these  lines  are  under  ground,  no  "  preliminary  "  current  is  necessary. 

The  mechanical  operation  of  the  apparatus  is  as  follows  :  On  the 
clock  (R,  Fig.  9)  there  is  an  ebonite  wheel  ( W)  in  which  are  two  notches 
(N,  N')  corresponding  to  10  a.  m.  and  1  p.  m.  Shortly  before  10  a.  m. 
the  pin  (P)  on  one  arm  of  the  forked  lever  (L)  falls  into  the  notch  (N), 
allowing  the  end  (Q)  of  the  other  arm  to  rest  on  the  ebonite  hour- 
wheel  (T).  About  two  minutes  before  the  hour,  the  end  (Q)  comes 
against  the  contact  (S),  and  completes  the  circuit  of  the  local  bat- 
tery (U,  Fig.  8)  through  the  starting  magnet  (M,  Fig.  9)  and  sets  the 
clock-train  (shown  in  Fig.  7)  in  motion,  pressing  the  cam  (C)  against  the 
vertical  bars,  disconnecting  them  from  their  instruments,  and  connect- 
ing them  respectively,  in  groups  as  already  shown,  with  the  relays 
(V,  V,  V"),  in  readiness  to  send  a  "  preliminary  "  current  to  the  line 
wires.  At  ten  seconds  to  the  hour  an  insulated  pin  (^,  Fig.  9)  on  the 
wheel  (T)  lifts  the  lower  arm  of  the  forked  lever  (F),so  that  its  upper 
arm  comes  in  contact  with  a  small  cam  on  the  arbor  of  the  escape- 
wheel  (K).  This  contact  closes  the  circuit  of  the  battery  (U)  through 
the  coils  of  the  two  relays  (Z,  Z').  The  relay  (Z)  puts  on  the  earth  con- 
nection at  (E),  for  the  four  relays  (Y,  Y,'  Y",  Y'"),  so  that  the  current 
from  Greenwich  may  be  received  and  divided  between  them,  while 
the  relay  (Z')  disconnects  the  Westminster  clock-wire  and  connects  it 
with  the  metropolitan  lines  to  receive  the  signal  from  the  relay  (Y'"). 
The  relays  (Y,  Y',  Y",  Y'")  have  a  resistance  of  5,000  ohms  to  allow 
of  the  splitting  of  the  current.  At  precisely  ten  o'clock  the  Green- 
wich signal  reverses  the  current  on  the  lines,  and  thus  gives  the  exact 
time.  At  ten  seconds  past  the  hour  the  contact  between  H  and  K  is 
broken,  the  relay-bars  go  back  to  their  normal  position,  the  train - 
work  moves  away  the  cam  (C),  and  restores  the  vertical  bars  to  con- 
nection with  their  instruments. 

The  apparatus  which  effects  the  shunting  at  one  o'clock  is  somewhat 
2 


18 


TIME-KEEPING   IN    LONDON. 


diflPerent  in  construction.    The  pin  (P,  Fig.  9)  falls  into  the  notch  (N'), 
a  pin  (p)  on  the  wheel  (W)  coming  against  the  arm  (I)  of  the  forked 


Fig,  9.— Diagram  showing  Electric  CoNNECTiONe  of  Clock  with  Chronopher. 


lever  (Y)  raises  the  flexible  arm  (G)  against  the  upper  contact  (D),  so 
that  the  circuit  of  the  local  battery  (U)  is  closed  through  the  starting 
magnet  (M),  which  operates  the  one  o'clock  train-work. 

Wires  which  receive  both  the  ten  and  one  o'clock  signals  pass 
through  both  switching  arrangements. 

For  the  hourly  currents  on  metropolitan  lines  the  relay  (V")  serves, 
by  closing  the  circuit  of  the  battery  (U)  at  the  contact  (K),  the  rest 
of  the  apparatus  remaining  inoperative. 


TIME-KEEPING   IN   LONDON.  19 

The  actual  interval  during  which  the  Greenwich  as  well  as  the  pro- 
Tincial  wires  on  which  the  time-signal  is  distributed  are  kept  in  circuit 
being  only  twenty  seconds,  the  chance  of  interruption  from  contact 
■currents  is  reduced  to  a  minimum. 

The  batteries  in  use  are  large  Leclanche  cells,  and  the  power  is 
distributed  as  follows  : 

Copper  or  "  time  "      Zinc  or  "  preliminary  " 
battery.  battery. 

Long  lines 80  cells.  60  cells. 

Medium  lines 60     "  45     « 

Short  lines 40     "  30     " 

Metropolitan  lines 40     "  . .     " 

The  Greenwich  signal,  thus  distributed  by  the  chronopher,  goes  to 
all  parts  of  the  kingdom,  and  affects  receiving  instruments  provided 
for  the  purpose.  These  are  of  various  kinds  ;  ordinary  telegraphic 
sounders,  electric  bells,  and  galvanometers  have  been  used  with  suc- 
-cess  to  note  the  arrival  of  the  signal.  The  current  has  also  been  made 
to  drop  time-balls  on  the  tops  of  buildings,  to  expose  a  model  time- 
ball  to  view,  and  to  fire  guns. 

To  test  the  accuracy  of  the  signals,  experiment  has  been  made  by 
returning  a  wire  to  Greenwich  from  the  chronopher,  and  comparing 
the  signal  received  on  this  wire  with  the  signal  sent  from  the  observ- 
atory ;  no  difference  could  be  perceived  between  the  indications  of 
two  galvanometers  placed  side  by  side  showing  the  passage  of  both 
currents.  The  signals  were  thus  shown  to  be  entirely  reliable.  But 
it  does  not  seem  likely  that  the  chronopher  will  be  introduced  else- 
where, because  simpler  means  have  been  devised  for  splitting  up  the 
•current  and  distributing  the  signals. 

The  whole  system  is  under  the  control  of  the  Post-Office  Depart- 
ment. They  own  the  wires — which,  except  in  London,  are  the  ordi- 
nary telegraph-wires — and  therefore  contract  to  keep  them  in  order, 
to  clear  them  each  day  at  the  signal-times,  and  to  deliver  at  these  times 
the  Greenwich  signal.  Maintenance  of  lines  and  apparatus  not  the 
property  of  the  department  is  undertaken  by  the  department  for  any 
period  not  less  than  one  year  at  specified  rates.  A  simple  form  of 
agreement  has  been  prepared,  which  every  renter  is  required  to  sign. 
This  agreement,  as  a  rule,  is  for  not  less  than  three  years,  and  is  ter- 
minable at  three  months'  notice  given  previous  to  the  end  of  the  fixed 
term,  or,  failing  such  notice,  on  payment  of  such  sum  as  the  depart- 
ment may  accept  instead.  But  where  the  expense  of  construction  is 
considerable,  the  term  must  not  be  less  than  from  five  to  seven  years, 
the  latter  period  being  stipulated  when  the  proposed  line  is  in  an  out- 


20  TIME-KEEPUSTG   IN    LONDON. 

lying  district  and  would  be  specially  provided  for  a  single  renter,  and 
when  it  is  not  probable  that  there  would  be  other  renters. 

The  annual  charges  for  the  use  of  wires  and  apparatus  are  as  fol- 
lows : 

From  London  to  the  country  :  *  For  the  10  a.  m.  signal,  £12  to 
£17  =  160  to  $85.  For  the  1  p.  m.  signal,  £27  to  £32  =  $135  to  $160. 
In  London  :  For  the  hourly  signal  within  a  radius  of  two  miles  from 
the  General  Post-Office,  £15  =  $75.  But  if  the  person  desiring  the 
signal  is  off  the  line  of  the  telegraph,  he  must  pay,  besides  a  stipulated 
rental,  an  additional  sum  for  the  use  of  the  wire  which  the  department 
is  compelled  to  put  up  specially  for  him.  The  rental  is  in  all  cases- 
payable  yearly  in  advance. 

In  1880  there  were  one  hundred  subscribers  to  the  system,  of  whom 
nineteen  were  in  London,  and  eighty-one  scattered  through  England^ 
with  a  few  in  Scotland  and  Ireland. 

Besides  this  general  automatic  distribution  of  the  time-signals,  a 
considerable  distribution  of  the  10  a.  m.  signal  goes  on  by  hand.  At 
that  instant  the  chronopher  makes  a  sound  which  an  operator  sits 
ready  to  catch  by  ear.  Upon  hearing  it  he  immediately  dispatches  a. 
signal  by  the  ordinary  telegraphic  instrument,  and  this  signal  is  received 
at  six  hundred  or  more  places,  which  again  serve  as  distributing  points, 
for  more  distant  places.  These  are  usually  railway  or  post  offices  in 
towns  not  supplied  by  the  chronopher,  which  by  virtue  of  authority 
become  the  regulators  of  the  clocks  of  the  surrounding  district. 

The  wire  from  the  observatory  to  London  Bridge  carries  signals 
hourly  from  the  mean  solar  standard  to  a  clock  at  the  station  of  the 
Southeastern  Railway,  which  by  changing  connections  sends  Greenwich 
time  to  different  stations  along  the  line  as  may  be  required.  For  this 
service  the  Southeastern  Railway  gives  the  observatory  the  use  of  its 
wire  daily,  for  a  few  minutes,  at  1  p.  m.  At  this  time  the  current 
from  the  observatory  drops  the  time-ball  at  Deal,  which  was  erected 
in  1855,  to  give  time  to  the  shipping  in  the  Downs,  and  is  the  only 
official  coast  time-signal.  The  ball  in  falling  sends  a  "  return  "  signal 
to  the  observatory.  The  record  shows  that  about  once  in  two  months 
high  wind  prevents  the  raising  of  the  ball,  about  once  in  six  weeks  it 
fails  to  fall  on  account  of  some  fault  in  the  electric  connections,  and 
about  once  a  year  it  drops  out  of  time.  Under  such  circumstances  it 
is  dropped  correctly  at  2  p.  m. 

*  DiflPerence  in  charge  for  the  same  signal  depends  on  the  length  of  wire  which  the 
department  is  compelled  to  put  up  specially  for  the  subscriber.  The  one  o'clock  signal 
is  more  expensive,  because  the  wires  are  busier  with  telegraph  duties  at  that  hour  than 
at  10  A.  M. 


^< 


wJ 


TIME-KEEPING   IN    LONDON. 


21 


By  special  arrangement  with  the  observatory  a  few  London  jewel- 
ers receive  the  hourly  Greenwich  current  on  private  wires.  This, 
they  use  for  the  correction  of  their  own  time-keepers  and  in  some 
cases  for  distribution.  Prominent  among  these  are  the  Messrs.  Barraud 
&  Lund,  of  Cornhill,  who  have  patented  a  method  for  the  synchroni- 
zation of  clocks.  Their  plan  is  put  forward  as  a  simple  and  effectual 
means  of  setting  any  number  of  ordinary  clocks  to  the  same  standard 
time.  All  attempts  to  control  clocks  have  been  set  aside  as  imprac- 
ticable, and  a  system  adopted  whereby  the  clock  is  automatically 
"  set  to  time  "  every  hour,  or  at  such  intervals  as  may  be  arranged. 
The  apparatus  can  here  be  described  only  in  brief.  There  are  three 
essential  parts,  the  standard  dock,  the  distributor,  and  the  synchro- 
nizer. 

The  standard  clock  is  an  astronomical  regulator  with  mercurial 
pendulum  and  dead-beat  escapement,  and  closes  an  electric  circuit  at 
the  sixtieth  second  of  each  hour.  Another  regulator,  technically  called 
"  Lobby,"  is  for  use  in  case  of  accident  to  "  Standard."  They  are  so 
connected  that  a  single  failure  of  "  Standard  "  to  send  out  a  signal  at 
the  proper  time  brings  "  Lobby  "  into  action  for  the  next  signal,  and, 
in  order  that  "  Lobby  "  may  always  be  ready  for  service,  an  inten- 
tional breakdown  of  "  Standard  "  occurs  automatically  at  eight  each 
morning,  and  the  nine  o'clock  signal  is  sent  out  by  "  Lobby  "  ;  which 
of  the  two  is  in  operation  is  shown  by  indicators  connected  with  the 
clocks  (Fig.  10).*  Should  a  breakdown  occur,  the  indicator  of  "  Stand- 
ard "  would  show  missed,  and  that  of  "  Lobby  "  at  worJc. 


1                       .1 

^ 

^ 

Fig.  10.— Bakraud  and  Lund's  Indicators. 


The  error  of  the  standard  clock  is  determined  daily  by  comparison 
with  the  Greenwich  signal.  An  ordinary  dotting  chronograph  is  set 
to  the  standard  clock,  and  the  Greenwich  signal  makes  a  dot  on  the 


*  Figs.  10,  11,  12,  and  13,  have  been  reduced  from  drawings  in  "  The  Railway  Engi- 
neer," London,  by  permission  of  Messrs.  Barraud  &  Lund. 


22 


TIME-KEEPING   IN    LONDON. 


'Cbronograph-dial  whicli|give8  at  once  the  error  of  the  standard  and 
can  be  read  off  at  leisure.  It  is  corrected  by  electric  means.  The 
pendulum  carries  a  small  permanent  magnet  which  swings  over  a  re- 


ffl 


-7 


Fig.  11,  —Test-Box. 


sistance-coil  about  -^  inch  distant.  The  coil  is  connected  with  the 
commutator  in  the  test-box  (Fig.  11),  consisting  of  a  clock  commuta- 
tor jwith  plugs  for  "  Standard  "  and  "  Lobby,"  a  current  commutator 


TIME-KEEPING   IN   LONDON. 


Fig.  12.— The  Stnchkonizer. 


254:  TIME-KEEPING   IN    LONDON. 

with  plugs  for  "  Fast "  and  "  Slow,"  and  a  small  time-piece,  shown  at 
the  top.  The  time-piece  has  only  a  minute-hand,  and  is  made  so  as  to 
stop  itself  and  break  circuit  at  XII,  but  closes  circuit  when  running. 
The  working  is  thus  :  Suppose  "  Standard  "  is  found  to  be  slow.  Plugs 
are  inserted  for  "  Standard  "  and  "  Slow,"  and  the  hand  of  the  time- 
piece is  set  back  a  required  number  of  minutes.  It  then  runs  to  XII 
and  stops.  In  this  interval  the  action  between  the  magnet  and  the 
coil  has  exactly  corrected  the  standard  clock.  For  every  -^  second  of 
error  the  hand  of  the  time-piece  must  be  set  back  five  minutes.  When 
the  setting  is  done,  no  further  attention  is  required,  all  else  being 
automatic. 

The  distributor  (shown  in  Fig.  11)  consists  of  twelve  contact- 
springs,  each  connected  with  a  line  of  wire  running  through  a  district 
of  London,  and  twelve  contact-screws,  each  connected  with  a  battery. 
The  springs  converging  to  the  center  press  up  against  a  small  plate, 
one  inch  in  diameter,  which  is  controlled  by  an  electro-magnet  in  the 
circuit  of  the  current  which  the  standard  clock  sends  out  hourly. 
When  the  signal  comes,  the  plate  is  pulled  down  and  presses  every 
spring  against  its  contact-screw,  and  the  signal  goes  out  over  each  of 
the  lines. 

The  synchronizer  is  the  receiver  of  the  signal,  and  consists  essen- 
tially of  an  electro-magnet,  in  the  circuit  of  one  or  other  of  the  lines 
from  the  distributor,  with  armature  carrying  two  counterpoised  levers 
each  provided  with  a  projecting  pin.  When  the  signal  arrives,  the 
electro-magnet  attracts  its  armature,  and  the  two  pins  are  brought 
close  together.  The  mechanical  operation  will  be  understood  by  ref- 
erence to  Fig.  12,  where  a  side  elevation,  a  plan,  and  a  front  elevation 
are  shown.  This  apparatus  is  fastened  to  ordinary  clocks  just  back  of 
the  dial-plate  (Fig.  13).  A  curved  slot  is  cut  through  the  dial  for  a 
short  space  on  each  side  of  XII,  and  through  this  the  pins  project. 
When,  at  the  end  of  the  hour,  the  signal  arrives,  the  two  pins  are 
pushed  together  and  bring  the  minute-hand  exactly  to  XII.  The  posi- 
tion of  the  pins  before  and  just  after  the  operation  is  shown  in  Fig. 
14.  Evidently  the  clock  must  not  be  in  error  more  than  two  minutes 
or  so  ;  but,  as  the  hand  is  set  every  hour,  any  ordinary  clock  can  be 
kept  right  by  this  device. 

Other  ingenious  arrangements  have  been  added  to  guard  against 
danger,  always  present  to  long  lines  of  wire,  and  for  testing  the 
condition  of  the  lines,  but  a  description  of  them  can  not  here  be 
given. 

The  advantages  claimed  for  the  system  are  : 


TIME-KEEPING   IN    LONDON. 


25 


1.  That  any  number  of  clocks  of  any  varying  sizes  can  be  syn- 
chronized to  any  agreed  standard  time-keeper. 


Fig.  13.— Face  of  Clock  with  Synchronizer  attached, 

2.  That  the  mechanism  is,  when  not  in  momentary  use,  entirely 
detached  from  the  works  of  the  clock. 

3.  That  it  can  be  applied  to  existing  clocks. 


c  Dc 


Fig.  14. 

4.  That  any  failure  in  the  transmission  of  the  time-current  leaves 
the  clock  going  in  the  ordinary  way,  to  be  "  set  to  time  "  by  the  next 
completed  current. 

5.  That  the  clocks  are  kept  to  time  whether  having  otherwise 
either  a  gaining  or  losing  rate,  even  if  such  rate  amounts  to  many 
minutes  a  day. 

In  London  the  system  has  been  in  successful  operation  for  about 
five  years,  and  has  been  used  over  a  wire  four  hundred  miles  long. 


26 


TIME-KEEPING   IN    LONDON. 


The  subscribers  number  about  five  hundred,  among  them  many  rail- 
roads and  public  institutions. 

In  connection  with  the  synchronized  clocks,  Messrs.  Barraud  and 
Lund  have  also  established  time-bells  and  flashing-signals,  which  afford 


Fig.  15.— Baeraud  and  Lund's  TiME-BBLii. 


time-signals  both  to  the  ear  and  eye.  These  are  shown  in  Figs.  15  and 
16.  The  bell  is  an  ordinary  electric  bell,  and  is  rung  by  the  regulat- 
ing clock,  which  closes  the  circuit  at  the  instant  the  signal  is  desired. 
The  flashing-signal  consists  of  a  red  vertical  disk  on  a  vertical  axis, 
which  normally  shows  only  its  edge,  but  is  made  to  revolve  once  on 
its  axis  in  four  sudden  jumps,  by  simple  mechanism  in  connection  with 
electro-magnets,  when  the  regulator,  by  closing  the  circuit,  sends  the 
current.  The  appearance  is  that  of  two  flashes  of  red  as  the  disk 
revolves. 


TIME-KEEPING   IN   LONDON. 


27 


In  many  places  where  noise  prevents  hearing  a  bell,  the  flashing- 


signal  becomes  a  necessity, 
change,   and    serves   to   indi- 
cate    the     exact     instant    of 
noon. 

The  method  of  synchroniz- 
ing clocks  is  becoming  rapidly 
popular  throughout  the  world, 
and  has  been  patented  in  most 
civilized  countries.  It  is  al- 
ready in  use  in  Australia  and 
South  America,  and  in  some 
of  the  countries  on  the  Conti- 
nent of  Europe.  In  this  coun- 
try, at  New  Haven,  Connecti- 
cut, a  "  Standard  Time  Com- 
pany "  has  been  formed,  who 
have  bought  the  patent  for 
the  whole  of  the  American 
Continent,  and  are  now  en- 
gaged in  manufacturing  syn- 
chronizers. An  effort  will  be 
made  by  them  to  bring  about 
a  concerted  system  of  time- 
signaling  throughout  the  coun- 
try. Local  affiliated  compa- 
nies will  be  formed,  and  there 
is  little  doubt  that  the  great 
simplicity  and  practical  suc- 
cess of  the  method,  combined 
with  its  cheapness,  will  se- 
cure its  extensive  adoption 
in  all  the  large  cities  of  the 
country. 


It  is  in  use  at  the  London  Stock  Ex-^ 


/ 


^>* 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 
LOAN  DEPT. 

This  book  is  due  on  the  last  date  stamped  below,  or 
on  the  date  to  which  renewed. 
Renewed  bocks  are  subjea  to  immediate  reeall 


LD 


DEC  2  0  1957 


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-MAR  10  1959- 


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General  Library 

University  of  Calif ornii 

Berkeley 


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